Vertical shaft pump

Abstract

To provide a vertical shaft pump that suppresses the temperature rise of sliding members and improves the lifespan of sliding members. [Solution] The vertical shaft pump 100 of the present invention comprises a rotating shaft 1 extending in the vertical direction, an impeller 2 fixed to the lower end side of the rotating shaft 1, and a bearing device 7 supporting the rotating shaft 1. The bearing device 7 uses pumped water as a lubricant during pumping operation and operates with unlubricated sliding without lubricant during idling operation, and has a bearing portion 20 that slides with the rotating shaft 1 and a buffer portion 30 that holds the bearing portion 20 from the outer circumference. The bearing portion 20 has a bearing sliding member 21 and a back metal 22 that holds the bearing sliding member 21 from the outer circumference. The buffer portion 30 has an elastic member 31 and a buffer portion back metal 32 that holds the elastic member 31 from the outer circumference. A plurality of ventilation holes 51 extending in the direction of the rotating shaft 1 are provided on the inner circumference side of the elastic member 31.

Description

Technical Field

[0001] The present invention relates to a vertical pump.

Background Art

[0002] In recent years, with global warming due to excessive CO2 emissions, disasters caused by abnormal weather have occurred frequently. For example, during heavy rainstorms in urban areas, the inflow of rainwater into drainage pump stations (hereinafter simply referred to as drainage stations) is large and rapid. Therefore, the risk of urban floods is increasing. In order to avoid the occurrence of such urban floods, a drainage pump that can operate quickly and drain water even in an emergency is required. Therefore, during normal times when no flood has occurred, an idling operation of a drainage pump such as a vertical pump installed in a drainage station is carried out for operation confirmation.

[0003] In addition, in order to prevent waterlogging damage due to a delay in starting the drainage pump against a sudden and large inflow of rainwater into the drainage pump station, the drainage pump is idled and put into standby operation before the rainwater flows into the drainage station so that it can drain water immediately when water comes out. There is a strong demand for a pre-standby operation. In a pre-standby operation type vertical pump that performs pre-standby operation, the idling operation time during which pumping is not performed becomes long. Therefore, as a bearing device of the pump, in a sliding bearing that uses pump pumping as a lubricating fluid, non-lubricated sliding without lubricating fluid in the bearing device will continue for a long time. As a result, heat is generated by frictional sliding, which may affect the life of the bearing device and the like.

[0004] On the other hand, for example, there is a technique described in Patent Document 1. In the vertical pump described in Patent Document 1, in a bearing (9) arranged to face the outer peripheral surface of the rotating shaft (2) of the vertical pump, a bearing holding member (13) arranged on the outer peripheral surface of the bearing (9), and a plurality of elastic bodies (15) (FIG. 2B) arranged with a gap in the circumferential direction on the outer peripheral surface of the bearing holding member (13), and an elastic body holding member (14) arranged on the outer peripheral surfaces of the plurality of elastic bodies. With such a configuration, it is said that the temperature rise of the bearing can be suppressed and the life can be extended. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-170879 (Figures 1, 2A, 2B, paragraphs 0016-0021) [Overview of the project] [Problems that the invention aims to solve]

[0006] However, in the vertical shaft pump described in Patent Document 1, sufficient consideration was not given to guiding airflow into the gap of the elastic body (15) (Figure 2B). As a result, when the vertical shaft pump was operated continuously for a long period of time, the cooling of the bearing (9) was insufficient, and the sleeve (8) of the bearing sliding member reached the end of its lifespan prematurely.

[0007] The present invention aims to solve the above problems and to provide a vertical shaft pump that suppresses the temperature rise of the sliding member and improves the lifespan of the sliding member. [Means for solving the problem]

[0008] To solve the aforementioned problems, the vertical shaft pump of the present invention comprises a rotating shaft extending in the vertical direction, an impeller fixed to the lower end of the rotating shaft, and a bearing device supporting the rotating shaft. The bearing device has a bearing portion that slides with the rotating shaft and a buffer portion that holds the bearing portion from the outer circumference. The bearing portion has a bearing sliding member and a back metal that holds the bearing sliding member from the outer circumference. The buffer portion has an elastic member and a buffer portion back metal that holds the elastic member from the outer circumference. The inner circumference of the elastic member is provided with a plurality of ventilation holes extending in the direction of the rotating shaft. During pumping operation, pumped water is used as a lubricant, and during idling operation, the pump operates with unlubricated sliding without lubricant. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a vertical shaft pump that suppresses the temperature rise of the sliding member and improves the lifespan of the sliding member. [Brief explanation of the drawing]

[0010] [Figure 1] This is an overall configuration diagram of a vertical shaft pump according to the first embodiment of the present invention. [Figure 2] This is an enlarged cross-sectional view of a key part showing the bearing device in a vertical shaft pump according to the first embodiment. [Figure 3] Figure 2 is a cross-sectional view of bearing device II. [Figure 4] This is an enlarged cross-sectional view of a key part showing the bearing device of a second embodiment in a vertical shaft pump. [Figure 5] This is an enlarged cross-sectional view of a key part showing a bearing device of a third embodiment in a vertical shaft pump. [Figure 6] This is a cross-sectional view taken along line II-II of the bearing device of the third embodiment. [Figure 7] Figure 1 is an enlarged cross-sectional view of a key part showing a modified bearing device of the third embodiment in the vertical shaft pump. [Figure 8] This is a cross-sectional view taken along line III-III in Figure 7 of a modified example of the third embodiment. [Figure 9] Figure 1 is an enlarged cross-sectional view of the main part showing the bearing device of the fourth embodiment of the bearing device in the vertical shaft pump shown. [Figure 10] This is a cross-sectional view corresponding to line III-III in Figure 7 of the bearing device of the fifth embodiment of the bearing device in the vertical shaft pump shown in Figure 1. [Figure 11] Figure 10 is a conceptual diagram showing the airflow in the IV-IV section. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described below with reference to the drawings. In principle, the same reference numerals are used for identical elements in all drawings. Furthermore, descriptions of parts having the same function will be omitted. Note that the configurations described below are merely examples of embodiments, and the embodiments of the present invention are not intended to be limited to the following specific modes.

[0012] <<First Embodiment>> FIG. 1 is an overall configuration diagram of a vertical pump 100 according to a first embodiment of the present invention. The vertical pump 100 of the first embodiment is a pump having a vertical rotation axis 1, which pumps rainwater from sewage in a drainage station or the like and discharges it toward a river or the sea. The vertical pump 100 is installed on the floor portion 9a of the suction tank 9. The vertical pump 100 includes a motor 10, a rotation axis 1 of the drive shaft, an impeller 2 for scraping up rainwater, a pump casing 3, a lift pipe 4, and a discharge elbow portion 5.

[0013] The motor 10 is a drive source of the vertical pump 100. The rotation axis 1 is installed to extend in the vertical direction, is connected to the motor shaft 10j of the upper motor 10, and rotates. The impeller 2 is fixed to the lower end portion of the rotation axis 1 and rotates by the rotation of the rotation axis 1.

[0014] The pump casing 3 is a casing that covers the impeller 2 and the bearing device 6 near the impeller 2. On the suction port side of the pump casing 3, a suction bellmouth 3a for sucking in rainwater is provided. The lift pipe 4 is a straight pipe flow path for the rainwater pumped by the vertical pump 100. The lift pipe 4 is connected to the upper part of the pump casing 3 and extends further upward. The discharge elbow portion 5 is an elbow pipe that bends the rainwater flow path of the lift pipe 4 extending in the vertical direction to the horizontal direction. The discharge elbow portion 5 is connected to the upper part of the lift pipe 4 and forms an elbow joint. The above-described rotation axis 1 is rotatably supported by the bearing device 6 and the bearing device 7.

[0015] The bearing device 6 is fixed to the pump casing 3. The bearing device 6 is positioned near the impeller 2 and provides rotational support to the lower end of the rotating shaft 1. The bearing device 6 is fixed to the pump casing 3 via guide vanes 11 and the like. The bearing device 7 is fixed to the water pumping pipe 4. The bearing device 7 rotatably supports the central part of the rotating shaft 1 below the floor portion 9a of the suction tank 9 on the installation surface of the vertical shaft pump 100. The bearing device 7 is fixed to the water pumping pipe 4 via a support member 12. In this way, the rotating shaft 1 is supported by the bearing devices 6 and 7 inside the water pumping pipe 4 and is rotatable.

[0016] The prime mover, such as the motor 10 that drives the vertical shaft pump 100, is installed on a support base 15 erected on the floor 9a of the water intake tank 9 for ease of maintenance. The rotating shaft 1 is rotationally driven by a prime mover such as a motor 10 via a coupling 8 of a shaft coupling that transmits torque (the product of force and the length of the arm).

[0017] <Details of the Vertical Shaft Pump 100> The vertical shaft pump 100 of the first embodiment is a vertical shaft pump that performs idling operation for operational verification, etc., or a vertical shaft pump of the standby operation type. Bearing devices 6 and 7 are sliding bearings. The bearing devices 6 and 7 are of a type that uses the pumped water as a lubricant during pumping operation and can operate without lubrication (dry operation) during idle operation.

[0018] Furthermore, as a vertical shaft pump of the standby operation type, for example, the known Japanese Patent Publication No. 6-213190 describes a system in which the impeller 2 is positioned below a water level corresponding to the minimum water level at which air would be drawn in from the suction bell mouth 3a of the pump casing 3 if the water level during pump operation is below that level, and a plurality of air inlet sections (not shown) are provided in the pump casing 3 below the impeller 2, and an intake pipe (not shown) is provided to the air inlet section, with one end connected and the other end open to the atmosphere.

[0019] <Bearing devices 6, 7> The configuration of the bearing device 6 or bearing device 7 according to the first embodiment will be explained using Figures 2 and 3 below.

[0020] Figure 2 is an enlarged cross-sectional view of the main part of the bearing device 7 in the vertical shaft pump 100 of the first embodiment. Although only the right half of the bearing device 7 is shown in Figure 2, the left half of the bearing device 7 has a similar configuration, so the left half is omitted from the illustration. Figure 3 is a cross-sectional view of bearing device 7 II shown in Figure 2. Although only the right half of bearing device 7 is shown in Figure 3, the left half of bearing device 7 has a similar configuration, so the left half is omitted from the illustration. Since the bearing device 6 shown in Figure 1 has the same configuration as the bearing device 7 shown in Figure 2, only the bearing device 7 will be described.

[0021] An annular shaft sleeve 13 is fitted and fixed to the outer circumferential surface of the rotating shaft 1, which is supported by the bearing device 7 shown in Figure 2. When the rotating shaft 1 has a shaft sleeve 13, the shaft sleeve 13 is also included in the term "rotating shaft 1". The shaft sleeve 13 is made of a superhard material with a Rockwell hardness of around 90, such as tungsten carbide, to prevent damage from pebbles and other debris getting trapped when rainwater is pumped up.

[0022] The bearing device 7 shown in Figures 2 and 3 is configured to have an annular bearing portion 20 and an annular buffer portion 30 that holds the bearing portion 20 from the outer circumference. <Bearing part 20>

[0023] As shown in Figure 3, the bearing portion 20 has an annular bearing sliding member 21 and an annular back metal 22. The annular bearing sliding member 21 is provided on the inner circumference side and is in sliding contact with the annular shaft sleeve 13. The annular back metal 22 is provided on the back side (outer circumference side) of the bearing sliding member 21 and holds the bearing sliding member 21. The bearing sliding member 21 may be made of, for example, a heat-resistant resin material reinforced with carbon fiber.

[0024] The back metal 22 is made of metal. Any metal material can be used for the back metal 22, as long as it meets the specified conditions such as rust resistance, heat resistance, resistance to deterioration over time, moisture resistance, strength, and lifespan. The bearing sliding member 21 and the back metal 22 are joined using shrink fitting, cold fitting, or other methods, taking advantage of the difference in expansion rates between the resin and the metal.

[0025] <Buffer section 30> The annular buffer portion 30 shown in Figure 3 is composed of an annular elastic member 31 and an annular buffer portion back metal 32. The annular elastic member 31 is provided on the back side (outer circumference side) of the bearing portion 20 and holds the bearing portion 20. The annular buffer back metal 32 is provided on the back side (outer circumference side) of the elastic member 31 and holds the elastic member 31.

[0026] The elastic member 31 is made of rubber, and materials such as NBR (synthetic rubber copolymerized from acrylonitrile and butadiene) and CR (chloroprene rubber) are used. The buffer back metal 32 is made of metal. The back metal 22 can be made of any metal material as long as it meets the specified conditions such as rust resistance, heat resistance, resistance to deterioration over time, moisture resistance, strength, and lifespan. The elastic member 31 and the buffer back metal 32 are joined together by vulcanization bonding or the like.

[0027] <Bearing housing 41> As shown in Figure 2, a bearing housing 41 that holds the cushioning back metal 32 is provided on the back side (outer circumference side) of the cushioning back metal 32. The bearing housing 41 is fixed to a support member 12 which is fixed to the water pumping pipe 4 shown in Figure 1 with bolts or the like.

[0028] The annular bearing sliding member 21 slides against the annular shaft sleeve 13, which is fitted and fixed to the rotating shaft 1, and functions as a sliding bearing. The bearing sliding member 21 uses the pumped water as a lubricant (a liquid interposed between the annular shaft sleeve 13 of the rotating shaft 1 and the bearing sliding member 21) during pumping operations such as pumping rainwater. On the other hand, the bearing sliding member 21 is made of a material that allows it to operate without lubrication during idle operation when pumping is not performed, without seizing or other problems occurring.

[0029] As shown in Figures 2 and 3, multiple ventilation holes 51, which are triangular prism-shaped spaces, are provided on the inner circumference of the annular elastic member 31. The ventilation holes 51 are formed by a groove 31m that forms a triangular prism-shaped space on the inner circumference of the elastic member 31 and the outer circumferential surface 22a of the annular back metal 22. Since multiple ventilation holes 51 face the outer circumferential surface 22a of the annular back metal 22, good heat exchange occurs between the back metal 22 and the air flowing through the ventilation holes 51. Therefore, the back metal 22 and the bearing sliding member 21 can be effectively cooled by heat exchange with the air flowing through the ventilation holes 51.

[0030] <Effects and Effects> In the vertical shaft pump 100, there are assembly deviations (assembly errors other than manufacturing tolerances). In addition, the vertical shaft pump 100 is subjected to radial fluid forces (pressure and shear force due to the fluid) acting on the impeller 2 attached to the lower end of the rotating shaft 1 in the radial direction (direction perpendicular to the rotating shaft 1). As a result, the axis of the shaft sleeve 13 and the axis of the bearing sliding member 21 are not necessarily parallel, and their relative positions are slightly tilted due to the inclination and deflection of the rotating shaft 1.

[0031] When the positional relationship between the shaft sleeve 13 and the bearing sliding member 21 as shown in Figure 2 is as described, a particularly strong force is applied to one side of the shaft, causing uneven contact between the axial upper end 21j or lower end 21k of the bearing sliding member 21 and the shaft sleeve 13. In particular, during idling operation without lubrication, which is characteristic of the vertical shaft pump 100 of the standby type pump, the amount of frictional heat generated by sliding (product of dynamic friction force and distance traveled ∝ thermal energy) at the strongly contacting parts (the contact points between the axial upper end 21j or lower end 21k of the bearing sliding member 21 and the shaft sleeve 13) becomes especially large. The temperature of the bearing sliding member 21 in this part rises particularly high, increasing the risk of bearing damage such as seizure.

[0032] To avoid such partial contact between the shaft sleeve 13 and the bearing sliding member 21 with strong force, an elastic member 31 made of rubber material that deforms flexibly with internal friction is provided in the buffer portion 30. Since the elastic member 31 is an elastic body, it deforms in proportion to the force applied. The elastic deformation of the elastic member 31 allows the bearing section 20 to change its orientation.

[0033] Therefore, when the annular shaft sleeve 13 and the annular bearing sliding member 21 come into contact, the elastic member 31 of the buffer portion 30 deforms due to the contact force so that the axis of the shaft sleeve 13 and the axis of the bearing sliding member 21 become parallel, changing the orientation of the bearing portion 20. In this way, the shaft sleeve 13 and the bearing sliding member 21 of the rotating shaft 1 come into even contact in the direction of the rotating shaft 1. As a result, the frictional heat generated by sliding is evenly distributed in the axial direction. Therefore, the presence of the elastic member 31 prevents the generation of excessive frictional heat due to localized strong force contact caused by uneven contact, and the resulting damage due to excessive localized bearing temperature rise.

[0034] Furthermore, the frictional heat generated uniformly in the direction of the rotation axis 1 (product of kinetic friction force and distance traveled ∝ thermal energy) is conducted from the annular bearing sliding member 21 to the annular back metal 22 on the outer circumference, and the back metal 22 is cooled by heat exchange with the air flowing upward through the ventilation holes 51. Due to the rotation of the impeller 2 (see Figure 1), there is an upward airflow, so air flows in from the lower opening 51a (see Figure 2) of the ventilation holes 51 and flows out from the upper opening 51b. The upward airflow within the ventilation hole 51 is amplified by the warming of the air due to the heat dissipated from the outer surface of the back metal 22 by frictional sliding, which creates an upward airflow.

[0035] The upward airflow within the ventilation holes 51 facilitates heat exchange between the air and the back metal 22, thereby cooling the back metal 22 and the bearing sliding member 21, which is heat-conducted to the back metal 22. This suppresses the rate at which the bearing portion 20 rises in temperature. Furthermore, if the frictional heat generated by the sliding of the bearing sliding member 21 temporarily increases due to variations in the contact state between the annular shaft sleeve 13 and the annular bearing sliding member 21 as shown in Figure 2, the back metal 22 acts as a heat sink (heat sink) made of metal with high thermal conductivity, thereby suppressing the temperature rise of the bearing sliding member 21.

[0036] As described above, by using the bearing devices 6 and 7 of the first embodiment, even if the vertical shaft pump 100 is operated idly for a long period of time without lubricating fluid, excessive temperature rise of the bearing portion 20 and the resulting damage to the bearing portion 20 can be avoided, and the lifespan of the bearing sliding member 21 can be improved. Therefore, the reliability of the vertical shaft pump 100 (see Figure 1) can be improved.

[0037] <<Second Embodiment>> Figure 4 is an enlarged cross-sectional view of the main part showing the bearing device 17 of the second embodiment in the vertical shaft pump 100 (see Figure 1).

[0038] The configuration of the bearing device 16 or bearing device 17 according to the second embodiment will be explained with reference to Figure 4. In the following description, the bearing device 17 of the second embodiment shown in Figure 4 will be described as being the same as the bearing device 7 shown in Figure 1, but the bearing device 16 has a similar configuration. Note that only the right half of the bearing device 17 is shown in Figure 4, but the left half has a similar configuration, so the left half is omitted from the illustration.

[0039] In the second embodiment, an annular guide 61 with a substantially triangular cross-section is provided on the bottom surface of the bearing portion 20 of the bearing device 17, which is configured similarly to the bearing device 7 of the first embodiment. The annular guide 61 is made of, for example, stainless steel and bolted to the back metal 22. The annular guide 61 may be integrally molded with the annular back metal 22, but it is easier to manufacture the guide 61 and the back metal 22 separately.

[0040] As shown in Figure 4, the guide 61 has a substantially conical ring shape. The outer diameter of the annular guide 61 is smaller on the side away from the bearing portion 20 than on the side in contact with the bearing portion 20. Furthermore, the guide 61 is positioned inside the outer peripheral surface 22a of the back metal 22 (on the side of the rotating shaft 1) so as not to block the ventilation hole 51. In the configuration described above, the air rising from below the bearing device 17 is guided along the outer surface of the annular guide 61, as shown by the dotted arrow in Figure 4, and flows into the vent hole 51 from below through the opening 51a. If the annular guide 61 is not present, the air will also be swirled and rotated along with the rotation of the rotating shaft 1 due to the viscosity of the air, even directly below the bearing device 17, i.e., near the lower opening 51a of the vent hole 51.

[0041] If the airflow in the rotational direction of the rotating shaft 1 is fast, it is difficult for air to flow into the vent hole 51 which is perpendicular to the rotational direction of the rotating shaft 1. Therefore, by providing a guide 61 with a roughly conical ring shape, the swirling flow of air is guided by contacting the guide 61, and the swirling flow of air weakens near the lower opening 51a of the vent hole 51, making it easier for the air to flow into the vent hole 51. In addition, because fluids containing air tend to flow along the wall surface due to their viscosity, the inflow of air into the vent hole 51 from below is promoted, and heat exchange between the air and the back metal 22 is promoted. Consequently, the cooling effect between the back metal 22 and the bearing sliding member 21 that conducts heat with the back metal 22 can be enhanced.

[0042] As described above, by using the bearing devices 17 and 16 of the second embodiment, the vertical shaft pump 100 can avoid excessive temperature rise of the bearing portion 20 and the resulting damage to the bearing portion 20 even during long periods of idling without lubricating fluid, thereby improving the lifespan of the bearing sliding member 21. Therefore, the reliability of the vertical shaft pump 100 can be further improved.

[0043] <<Third Embodiment>> The configuration of the bearing device 26 or bearing device 27 according to the third embodiment of the present invention will be described with reference to Figures 5 and 6.

[0044] Figure 5 is an enlarged cross-sectional view of the main part showing the bearing device 27 of the third embodiment of the bearing device 7 in the vertical shaft pump 100 shown in Figure 1. In the following description, the bearing device 27 shown in Figure 5 is described as being the same as the bearing device 7 shown in Figure 1, but the bearing device 26 of the third embodiment has a similar configuration. Note that only the right half of the bearing device 27 is shown in Figure 5, but the left half has a similar configuration, so the left half is omitted from the illustration.

[0045] The third embodiment is configured to have the same bearing portion 20 and cushioning portion 30 as the first embodiment, but differs from the first embodiment in the following respects. In the third embodiment, the axial lower surface of the rotating shaft 1 of the annular bearing portion 20 is in contact with the lower part of the bearing housing 41 via the lower annular elastic body 33. Furthermore, the axial upper surface of the rotating shaft 1 of the annular bearing portion 20 is covered by the annular bearing cover 42 via the upper annular elastic body 34.

[0046] Figure 6 is a cross-sectional view taken along line II-II of the bearing device 27 shown in Figure 5 of the third embodiment. Although only the right half of the bearing device 27 is shown in Figure 6, the left half has a similar configuration and is therefore omitted from the illustration. Both the lower annular elastic body 33 and the lower part of the bearing housing 41 are provided with through holes 52a having the same or substantially the same cross-section as the ventilation hole 51 which forms a triangular prism-shaped space (see Figure 3).

[0047] Furthermore, the through-hole 52b, which is a triangular prism-shaped space provided in the upper annular elastic body 34 and the annular bearing cover 42 shown in Figure 5, has the same or substantially the same cross-sectional shape as the cross-section of the triangular prism-shaped ventilation hole 51 (see Figure 3).

[0048] <Modified form of the third embodiment> The configuration of a bearing device 36 or bearing device 37 according to a modified example of the third embodiment of the present invention will be explained with reference to Figures 7 and 8 below.

[0049] Figure 7 is an enlarged cross-sectional view of a key part showing a modified bearing device 37 of the third embodiment of the bearing device 7 in the vertical shaft pump 100 shown in Figure 1. In the following explanation, the bearing device 37 shown in Figure 7 is described as being the same as the bearing device 7 shown in Figure 1, but the modified bearing device 36 has a similar configuration. Note that only the right half of the bearing device 37 is shown in Figure 7, but the left half has the same configuration, so the left half is omitted from the illustration.

[0050] In the modified example, the bearing portion 20 and the cushioning portion 30 are the same as in the first embodiment, but the following points differ from the first embodiment. In the modified example, the axial lower surface of the rotating shaft 1 of the annular bearing portion 20 is in contact with the lower part of the bearing housing 41 via the lower annular elastic body 33. Furthermore, the axial upper surface of the rotating shaft 1 of the annular bearing portion 20 is covered by the annular bearing cover 42 via the upper annular elastic body 34.

[0051] Figure 8 is a cross-sectional view taken along line III-III of Figure 7 of a modified example of the third embodiment. Note that Figure 8 only shows the right half of the bearing device 37; however, the left half has the same configuration, so it is omitted from the illustration. Both the lower annular elastic body 33 and the lower part of the bearing housing 41 are provided with through holes 62a having a cross-section that encloses the cross-section of the ventilation hole 51, which forms a triangular prism-shaped space (see Figure 3). The through holes 62a are holes with a circular cross-section that is larger than the cross-section of the triangular prism-shaped ventilation hole 51.

[0052] Both the upper annular elastic body 34 and the annular bearing cover 42 shown in Figure 7 are provided with through holes 62b having a cross-section that encloses the cross-section of the ventilation hole 51, which forms a triangular prism-shaped space (see Figure 3). The through holes 62b are holes with a circular cross-section that is larger than the cross-section of the triangular prism-shaped ventilation hole 51.

[0053] <Effects and Effects> According to the third embodiment and modification, the bearing portion 20 and the buffer portion 30 are held in place by the bearing cover 42 and the bearing housing 41 from the extending direction of the rotating shaft 1. This reduces the risk of the bearing portion 20 and the buffer portion 30 falling off in the extending direction (axial direction) of the rotating shaft 1, resulting in a highly reliable bearing device 27, 26, 37, 36. Furthermore, through holes 52a, 52b (third embodiment, Figures 5 and 6) having the same cross-section as the triangular prism-shaped ventilation hole 51, or through holes 62a, 62b (modified example, Figures 7 and 8) having a cross-section that encompasses the cross-section of the triangular prism-shaped ventilation hole 51, are provided in the lower annular elastic body 33, the lower part of the bearing housing 41, the upper annular elastic body 34, and the bearing cover 42. As a result, the back metal 22 is cooled by heat exchange between the back metal 22 and the air due to the convection of air flowing from bottom to top through the through holes 52a, 52b, 62a, and 62b. In addition, the bearing sliding member 21 is cooled by heat conduction with the back metal 22. Therefore, the rate of temperature rise of the bearing portion 20 can be suppressed, and the bearing portion 20 can be prevented from becoming too hot.

[0054] Here, in order to avoid obstructing the airflow into the ventilation hole 51, which is a triangular prism-shaped space, or in other words, to allow air to flow into the ventilation hole 51 smoothly, it is desirable that the cross-section of the through-hole 52b be either the same as or approximately the same as the cross-section of the ventilation hole 51 (see Figure 6), or a larger through-hole 62a, 62b (see Figure 8) that encompasses the cross-section of the ventilation hole 51. Furthermore, if the through holes 62a and 62b have a circular cross-section, as shown in the modified example in Figure 8, the through holes 62a and 62b can be easily processed or molded, improving productivity.

[0055] As described above, by using the bearing devices 26 and 27 of the third embodiment (Figures 5 and 6) and the modified bearing devices 36 and 37 (Figures 7 and 8), the vertical shaft pump 100 (see Figure 1) can avoid excessive temperature rise in the bearing portion 20 and the resulting heat-induced damage to the bearing portion 20, even when running idly for a long period of time without lubrication, thereby improving the lifespan of the bearing sliding member 21. Therefore, the reliability of the vertical shaft pump 100 can be improved.

[0056] <<Fourth Embodiment>> The configuration of the bearing device 46 or bearing device 47 according to the fourth embodiment of the present invention will be explained with reference to Figure 9.

[0057] Figure 9 is an enlarged cross-sectional view of the main part of the bearing device 47 of the fourth embodiment of the bearing device 7 in the vertical shaft pump 100 shown in Figure 1. In the following description, the bearing device 47 shown in Figure 9 will be described as being the bearing device 7 shown in Figure 1, but the bearing device 46 of the fourth embodiment of the bearing device 6 has a similar configuration. Note that only the right half of the bearing device 47 is shown in Figure 9, but the left half has a similar configuration, so the left half is omitted from the illustration. In the fourth embodiment, a guide 61 in the shape of a substantially conical ring with a substantially triangular cross-section is provided on the bottom surface 41a of the bearing housing 41 of the bearing device 47, which is configured in the same manner as in the third embodiment.

[0058] The outer diameter s2 of the outer surface 61a of the guide 61 is smaller on the side away from the bearing portion 20 than the outer diameter s1 on the side in contact with the bearing portion 20. In addition, the guide 61 is installed on the inside (closer to the rotating shaft 1) of the outer surface 22a of the back metal 22 so as not to block the through hole 52a.

[0059] <Effects and Effects> According to the fourth embodiment, the outer diameter s2 of the outer surface 61a of the guide 61 is smaller on the side away from the bearing portion 20 than the outer diameter s1 on the side in contact with the bearing portion 20. Also, since the guide 61 is installed inside (closer to the rotating shaft 1) of the outer surface 22a of the back metal 22, the guide 61 does not block the through hole 52a. Therefore, the air that swirls due to viscosity as it rotates with the rotation of the rotating shaft 1 is guided by the outer surface 61a of the guide 61 and easily flows from the through hole 52a into the triangular prism-shaped ventilation hole 51. As a result, the air flowing from bottom to top through the ventilation hole 51 exchanges heat with the back metal 22, which has been heated by the frictional heat of the bearing sliding member 21, and the back metal 22 is cooled. In addition, the bearing sliding member 21 is cooled by heat conduction between the back metal 22 and the bearing sliding member 21. Therefore, the cooling effect of the back metal 22 and the bearing sliding member 21 is enhanced.

[0060] As described above, the bearing devices 47 and 46 of the fourth embodiment prevent excessive temperature rise of the bearing portion 20 and the resulting damage to the bearing portion 20, even when the vertical shaft pump 100 is operated for a long period of time without lubricating fluid. Therefore, the reliability of the vertical shaft pump 100 can be improved.

[0061] <<Fifth Embodiment>> The configuration of the bearing device 56 or bearing device 57 according to the fifth embodiment of the present invention will be described with reference to Figures 10 and 11.

[0062] Figure 10 is a cross-sectional view corresponding to line III-III in Figure 7 of the fifth embodiment of the bearing device 57 in the vertical shaft pump 100 shown in Figure 1. In the following description, the bearing device 57 shown in Figure 10 will be described as being the same as the bearing device 7 shown in Figure 1, but the bearing device 56 of the fifth embodiment has a similar configuration. Note that only the right half of the bearing device 57 is shown in Figure 10, but the left half has a similar configuration, so the left half is omitted from the illustration. As shown in Figure 10, in the fifth embodiment, the lower annular elastic body 33 of the bearing device 57, which is configured in the same way as in the fourth embodiment, and the lower part of the bearing housing 41 are provided with a cylindrical through hole 52a with a circular cross-section.

[0063] The centroid Y of the circular cross-section of the through-hole 52a is configured to be on the opposite side of the rotation direction of the rotation axis 1 (arrow α11 in Figure 10) to the centroid X of the triangular cross-section of the ventilation hole 51, which is a triangular prism-shaped space formed by the elastic member 31 and the outer circumferential surface 22a of the back metal 22, relative to the rotation direction of the rotation axis 1.

[0064] Figure 11 is a conceptual diagram showing the airflow in the IV-IV section of Figure 10. <Effects and Effects> With this configuration, as the rotating shaft 1 rotates (arrow α11 in Figure 10), the air (arrow α12 in Figure 1) rising from below the bearing device 57 with a swirling motion flows into the cylindrical through-hole 52a, which opens from the upstream side of the flow (the side opposite to the rotation direction of the rotating shaft 1), as shown by arrow α13 in Figure 11. This facilitates the flow of air into the triangular prism-shaped vent hole 51 from below. As a result, heat exchange between the air flowing from bottom to top through the vent hole 51 (relatively low temperature) and the back metal 22 (relatively high temperature) is promoted, and the cooling effect of the back metal 22 and the bearing sliding member 21 that is in contact with the back metal 22 and undergoes heat exchange can be enhanced.

[0065] Therefore, by using the bearing devices 57 and 56 of the fifth embodiment, it is possible to avoid excessive temperature rise of the bearing portion 20 and the resulting damage to the bearing portion 20 even during prolonged idling without lubricating fluid in the bearing devices 57 and 56. This improves the reliability of the vertical shaft pump 100 (see Figure 1).

[0066] <<Other Embodiments>> 1. The present invention is not limited to the embodiments and modifications described above, but includes various modifications. For example, although the embodiments described above illustrate bearing devices 7 and 6 equipped with a back metal 22, the present invention can be similarly applied to bearing devices without a back metal 22.

[0067] 2. Furthermore, the present invention is not limited to the pre-operation type vertical shaft pump 100, and can be effectively applied to any vertical shaft pump equipped with a bearing device having bearing sliding members that use pumped water as a lubricant during pumping operation and can operate with unlubricated sliding without lubricant during idling operation.

[0068] 3. Furthermore, the embodiments and modifications described above are explained in detail for the purpose of clearly illustrating the present invention, and are not necessarily limited to those having all the configurations described.

[0069] 4. The present invention is not limited to the embodiments and modified configurations described above, and various modified and specific forms are possible within the scope of the appended claims. [Explanation of Symbols]

[0070] 1. Axis of rotation 2-blade wheel 3. Pump casing 3a Suction bell mouth 4. Water pumping pipe 5 Discharge elbow section 6, 7, 16, 17, 26, 27, 36, 37, 46, 47, 56, 57 Bearing device 8 Couplings 9 Water absorption tank 9a Floor 10 motors 11 Guide vanes 12 Support members 13 Axis Sleeve 15 Support stand 20 Bearing section 21 Bearing sliding member 22 Back Metal 22a Outer surface 30 Buffer 31 Elastic members 31m groove (ventilation hole) 32 Buffer back metal 33 Lower annular elastic body 34 Upper annular elastic body 41 Bearing housing 42 Bearing cover 51 Ventilation holes 52a, 52b, 62a, 62b through hole 61 Guide 100 Vertical shaft pump Centroid of the cross-section of the ventilation hole. Centroid of the cross-section of the Y-shaped through hole

Claims

1. It comprises a rotating shaft extending vertically, an impeller fixed to the lower end of the rotating shaft, and a bearing device supporting the rotating shaft. The bearing device is It has a bearing portion that slides with the rotating shaft and a cushioning portion that holds the bearing portion from the outer circumference. The bearing portion comprises a bearing sliding member and a back metal that holds the bearing sliding member from its outer circumference. The cushioning portion comprises an elastic member and a cushioning portion back metal that holds the elastic member from its outer circumference. The inner circumference of the elastic member is provided with a plurality of ventilation holes extending in the direction of the rotation axis, During pumping operations, the pumped water is used as a lubricant, while during idling operations, the system operates with unlubricated sliding without any lubricant. A vertical shaft pump characterized by the following features.

2. It comprises a rotating shaft extending vertically, an impeller fixed to the lower end of the rotating shaft, and a bearing device supporting the rotating shaft. The bearing device is It has a bearing portion that slides with the rotating shaft and a cushioning portion that holds the bearing portion from the outer circumference. The buffer portion has an elastic member provided with a plurality of ventilation holes extending in the direction of the rotation axis, During pumping operations, the pumped water is used as a lubricant, while during idling operations, the system operates with unlubricated sliding without any lubricant. A vertical shaft pump characterized by the following features.

3. In the vertical shaft pump according to claim 1, A guide is provided on the bottom surface of the bearing portion, and the outer diameter of the outer circumference of the side away from the bearing portion is smaller than the side that contacts the bearing portion. The guide is installed inside the outer surface of the back metal. A vertical shaft pump characterized by the following features.

4. A rotation axis extending vertically, An impeller fixed to the lower end of the aforementioned rotating shaft, The system includes a bearing device that supports the aforementioned rotating shaft, The bearing device is It has a bearing portion that slides with the rotating shaft and a cushioning portion that holds the bearing portion from the outer circumference. The bearing portion comprises a bearing sliding member and a back metal that holds the bearing sliding member from its outer circumference. The cushioning portion comprises an elastic member and a cushioning portion back metal that holds the elastic member from its outer circumference. The axial lower surface of the bearing portion faces the lower part of the bearing housing via a lower annular elastic body. The axial upper surface of the bearing portion is covered by a bearing cover via an upper annular elastic body. Multiple ventilation holes extending in the axial direction are formed on the inner circumference side of the elastic member. The lower annular elastic body, the lower part of the bearing housing, the upper annular elastic body, and the bearing cover are provided with through holes having a cross-section that is substantially the same as or encompasses the cross-section of the ventilation hole. During pumping operations, the pumped water is used as a lubricant, while during idling operations, the system operates with unlubricated sliding without any lubricant. A vertical shaft pump characterized by

5. A rotation axis extending vertically, An impeller fixed to the lower end of the aforementioned rotating shaft, The system includes a bearing device that supports the aforementioned rotating shaft, The bearing device is It has a bearing portion that slides with the rotating shaft and a cushioning portion that holds the bearing portion from the outer circumference. The buffer portion has an elastic member in which a plurality of vents extending in the axial direction are formed, The axial lower surface of the bearing portion faces the lower part of the bearing housing via a lower annular elastic body. The axial upper surface of the bearing portion is covered by a bearing cover via an upper annular elastic body. The lower annular elastic body, the lower part of the bearing housing, the upper annular elastic body, and the bearing cover are provided with through holes having a cross-section that is substantially the same as or encompasses the cross-section of the ventilation hole. During pumping operations, the pumped water is used as a lubricant, while during idling operations, the system operates with unlubricated sliding without any lubricant. A vertical shaft pump characterized by

6. In the vertical shaft pump according to claim 4, The bearing housing is provided with a guide whose outer diameter is smaller on the outer circumference of the side away from the bearing than on the side in contact with the bearing. The guide is installed inside the outer surface of the back metal. A vertical shaft pump characterized by the following features.

7. In the vertical shaft pump according to claim 4 or claim 5, The center of gravity of the cross-section of the lower annular elastic body and the through hole provided in the lower part of the bearing housing is located on the opposite side of the rotation axis to the center of gravity of the cross-section of the ventilation hole. A vertical shaft pump characterized by the following features.

8. In the vertical shaft pump according to claim 1 or claim 4, The ventilation holes face the back metal. A vertical shaft pump characterized by the following features.

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